获取Java中的二维数组的数组长度 [英] Getting the array length of a 2D array in Java

问题描述

我需要得到一个二维数组的长度为行和列两者。我已经成功地做​​到了这一点，用下面的code：

I need to get the length of a 2D array for both the row and column. I’ve successfully done this, using the following code:

public class MyClass {

 public static void main(String args[])
    {
  int[][] test; 
  test = new int[5][10];

  int row = test.length;
  int col = test[0].length;

  System.out.println(row);
  System.out.println(col);
    }
}

这打印出5，10符合市场预期。

This prints out 5, 10 as expected.

现在来看看这一行：

  int col = test[0].length;

请注意，我实际上是引用一个特定的行，为了得到列的长度。对我来说，这似乎令人难以置信的丑陋。此外，如果该阵列被定义为：

Notice that I actually have to reference a particular row, in order to get the column length. To me, this seems incredibly ugly. Additionally, if the array was defined as:

test = new int[0][10];

然后试图获得的长度时，code会失败。是否有不同的（更智能）的方式来做到这一点？

Then the code would fail when trying to get the length. Is there a different (more intelligent) way to do this?

推荐答案

考虑

public static void main(String[] args) {

    int[][] foo = new int[][] {
        new int[] { 1, 2, 3 },
        new int[] { 1, 2, 3, 4},
    };

    System.out.println(foo.length); //2
    System.out.println(foo[0].length); //3
    System.out.println(foo[1].length); //4
}

列长度每行不同。如果你被一个固定大小的二维数组支持的一些数据，然后提供给干将固定值的包装类。

Column lengths differ per row. If you're backing some data by a fixed size 2D array, then provide getters to the fixed values in a wrapper class.

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